My knowledge is that you pay a yearly membership fee (maybe $25). They will not tell you specifically where their locations are until you join. Also, most places do not offer any hookups, just a place to park and they hope you will buy something from their farm or winery.
Why not look at boondockerswelcome.com At least you can check on locations for where you are going. They now charge a yearly membership fee of $19.95. I got a free lifetime membership. This organization is only a little more than a year old and is growing.
From their website you can get specific information for where you choose to stay e.g. whether hookups are available, pets acceptable, BBQ use, parking surface, etc. We have stayed at a couple of places and it has worked out very well. Our hosts have been very congenial and helpful with local information.
Just another alternative for you to consider.
2014 Triple E Regency GT24MB (Murphy Bed) with all the good stuff
towing a 2016 Jeep Cherokee TrailHawk
Berkley, the amazing camping cat missed dearly (1996-2012)